Seat frame



FIG. 1 is a perspective view of a seat frame in accordance with the new design;

FIG. 2 is a top view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a left side elevational view thereof, a right side elevational view being a mirror image thereof; and,

FIG. 5 is a rear elevation view thereof. 

The ornamental design for a seat frame, as shown and described. 